if (File.Exists(Server.MapPath(filePath)))
        {
            string strFileName = Path.GetFileName(filePath).Replace(" ", "%20");
            Response.ContentType = "application/octet-stream";
            Response.AddHeader("Content-Disposition", "attachment; filename=" + strFileName);
            Response.Clear();
            Response.WriteFile(Server.MapPath(filePath));
            Response.End();//到此行也不报错  ,就直接没反应了
        }
window.showModalDialog()弹出的窗口  里面有下载链接 如何让这下载好用???求帮忙!!!